Cryptographic device



NOV. 29, 1938. J. c, WOBENSMH'H 2,138,532

- CRYPTOGRAPHIC DEV-ICE Filed Sept. ll, 1935 2 Sheets-Sheet 1 fiale/dor.'

lNew. 29, 1938. .1. c.l woBENsMlTH A CRYPTOGRAPHIC DEVICE 2 sheets-sheet 2 Filed sept. 11. 1935 Patented Nov. 29, 1938 UNITED STATES PATENT OFFICE 2,138,532 v caYP'roGRAPmc DEVICE James C. Wobensmith, Philadelphia, Pa.

Application September 11, 1935, Serial No. 40,170

15 claims.

The present invention relates to cryptographic devices, and more particularly to an improvedv coding and decoding device which is simple in construction. The invention particularly contemplates a cryptographic device which may be used for coding and decoding messages with greater facility than has heretofore been possible, vand by means of which cryptographic messages may be made up which are virtually impossible of solution without knowledge of the program used.

The invention further contemplates a cryptographic device which is adapted for use with a complicated program of character shifting. Other features will appear from the specification and claims.

'I'he nature and characteristic features of the invention will be more readily understood from the following description, taken in connection with the accompanying drawings forming part hereof, in which:

Fig. 1 is a top plan view, partly broken away, of a preferred embodiment of the invention;

Fig. 2 is a vertical central sectional view taken approximately on the line II-II of Fig. 1;

Fig. 3 is a vertical central sectional view taken approximately on the line III- III of Fig. 1;

Fig. 4 is a plan view of a disk or dial forming part of the present invention; and

Fig. 5 is a fragmentary plan view of a modified form of the invention.

It will, of course, be understood that the description and drawings herein contained are illustrative merely, and that various modifications and changes may be made in the structure disclosed without departing from the spirit of the invention.

Referring more particularly to the drawings, it will be seen that there is provided an upper cover sheet or plate IIJ, a lower sheet Il, and a disk I2. The upper cover sheet IIJ has a semicircular opening I3 extending therethrough. Characters corresponding to the letters of the alphabet as at I4, a space symbol or designation as at I5, and numerals as at I6, are disposed radially adjacent an outer edge of the opening I3. While these characters have been shown in their ordinary sequence, it will, of course, be understood that` any other preferred arrangement or grouping may be employed. Each of the characters corresponds to an angular unit fcn` cooperation with otherindicia as hereinafter pointed out. A plurality of slots of predetermined angular length to correspond to the characters on the upper plate I0 and the disk I2, is also provided. The slot I1 is preferably one angular unitv in length, the slot I8 two angular units, the slot I9 three angular units, the slot 20 four angular units, and the slot 2I five angular units.

The disk I2 preferably extends beyond the edges of the upper and lower cover sheets, as shown at 22, for facilitating the turning of the disk I2 by hand. If desired, however, the disk I2 may be completely within the edges.

The disk or dial I2 is provided with characters which may comprise the letters of the alphabet as at 23, a space symbol or stop designation as at 24, and numerals as at 25, although it will, of course, be understood that if desired, the numerals 25 and space symbol 24 may be omitted and the characters may be arranged in any desired sequence.

The indicia on the disk I2 preferably are the same as those appearing adjacent the semicircular opening I3 except that they are repeated so that the characters in their desired sequence appear at least twice. The disk I2 is provided with a plurality of apertures 26 at a uniform distance from the center, the ring of apertures thus being concentric with the characters 23, 24, and 25. An aperture 26 is provided to correspond lto each of the characters 23, 24, and 25 and thus witheach angular unit, and is adapted to receive the point of a stylus or other instrument for turning of the disk I2. The disk I2 has a central bearing aperture 21 for rotatably` mounting the same with respect to the top and bottom plates I0 and II by means of an eyelet, a rivet, or other suitable pivot device 28.

The upper and lower cover sheets I and IIl may be secured together in any suitable manner, but it has been found preferable to provide separating members 29 for insertion at the corners of the upper and lower sheets I0 and Il, these separating members 29 preferably being of greater thickness than the disk I2, and the sheets I0 and I I being secured thereto by a suitable adhesive.

In the modified form of the invention, as illustrated in Fig. 5, in lieu of the plurality of slots I'I, I8, I9, 20, and'2l in the top plate I0, a single slot 30 is provided, with suitable numerals and indicia disposed on either side thereof as a scale for guidance in shifting the disk I2. The numerals beyond the slot 30 may be arranged with the numbers 3| increasing toward the right and the numerals within the slot 30 may be arranged with the numbers 32 increasing toward the left.

The operation of the device will now be pointed out. In using the same for simple substitution cryptograms, the disk I2 is rotated to bring the characters thereon to the desired position with respect to the characters on the upper plate III. 'I'he message may then be encoded by substitution in the essage of the characters on the disk I2 which are in radial alinement with the characters on the upper plate I0. A full set of the characters on the disk I2 may be seen through the semicircular opening I3 in the upper plate I Il. The decoding of such a message is effected by locating the character of the message on the disl I2 and then referring toA the character corresponding thereto on the upper sheet III.

The structure of the present invention is, however, capable of much broader use and a program involving a predetermined advance or retrogression of the disk I2 may be employed. The disk I2 is arranged at a predetermined position as for simple substitution cryptograms and thereafter the disk I2 is partially rotated through a desired number of angular units clockwise or counterclockwise, in accordance with the number of such units previously agreed upon. 'I'he character on the disk I2 corresponding to the character to be ,encoded may then be readily ascertained and written down. The turning of the disk I 2 may be effected either by means of the portions 22 of the disk I2 which project beyond the upper and lower plates III and II or by inserting a stylus in an appropriate aperture 26 and moving the disk I2 the appropriate number of units, the length of the selected'slot permitting this to be done rapidly and accurately.

A message thus made up may be decoded by locating on the disk I2 the character of the message and then referring to the corresponding character on the upper sheet Ill and then, after making theproper angular shift of the disk as in encoding, repeating the operation.

aisssa the character "A" on the upper cover plate I0. The character corresponding to the numeral "5 of the message is then ascertained from the disk I2 as R. The disk I2 is now rotated ve angulax units clockwise by inserting a stylus in the aperture 26 at the left hand end of the slot 2| and moving the disk I2 around its axis until further movement is stop ed by contact of the stylus with the right hand end of the slot 2l. The character corresponding to the period or stop of the message is then ascertained to be H.

'I'he disk I2 is now rotated one angular unit by inserting the stylus in the aperture 26 at the left hand end of the slot I'I and moving the disk I2 clockwise on its axis until movement is stopped by contact of the stylus with the right hand end of the slot I1. The character corresponding to the character 2 of the message is ascertained to be I.

The 'disk I2 is now rotated two angular units by inserting the stylus in the aperture 26 at the left hand end of the slot I8 and moving the disk I2 on its axis until movement is stopped by contact of the stylus with the right hand end of the slot I8. The character 3 of the message is ascertained to be H.

The program is continued following the "5-1-2 clockwise sequence. To obtain the encoded character corresponding to the next character of the message the disk I2 is rotated five angular spaces by means of the stylus and the character corresponding to the space after the 3 is ascertained to be "9.

By following the program as heretofore set forth the message given above will appear in code, as fol1ows:`

The structure of the present invention is, in addition, capable of use with a more or less complicated program which will render the cryptogrammic message virtually impossible to decode If, in place of using the program heretofore given, the program given is counterclockwise W-5-l-2 the message would appear in code as follows:-

without a knowledge of the program. The program will ordinarily comprise an initial setting, together with a sequence of different shifts to be made after each character is written down. The shifting may be done by inserting a stylus in the aperture 26 at one end of the appropriate slot and rotating the disk I2 in a predetermined direction through the requisite number of angular units.

In order to illustrate more clearly the manner in which the structure may be used for encoding a message, it will be assumed that a program has been agreed upon, which may be designated as clockwise W-5-1-2, and that the message is as follows:

5.23 P. M. J. Q. Vandz struck my big fox whelp.

This` message may, if desired, be analyzed prior to the encoding.- The analysis in accordance with the program heretofore mentioned is as follows:

It is preferable to leave the message in the form shown above but if desired, the characters of the coded message may be separated into groups, either of the same or a different number of characters, or to convey information as to the program, which will be more confusing to a person unfamiliar with the program. Such a separation will not make more diilicult or affect in any manner the decoding of the message by one familiar with the program.

In decoding a message the program followed is very similar to that heretofore pointed out for the encoding. The initial letter setting is first effected and the characters of the message are located, after the proper angular movement has been made, on the disk I2 and from the disk I2, by reference to the corresponding characters on the upper sheet Ill, the original message may be ascertained. The direction of rotation of the disk I2 for decoding is the same as for encoding and in the same sequence.

W512512 51251251251251251251251251251251251251 5.25 P. M. J.Q. Vandz struck my big fox whelp.

Such an analysis is not, however, essential since the program may be followed without specinc reliance upon the analysis.

In following out the foregoing program, i. e. clockwise W--5-l-2, the disk I2 isset with the character W thereof in radial alinement with Of course, if desired, the agreed upon program may include certain movements of the disk I 2 in a clockwise direction and others ln a counterclockwise direction. l

In the use of the device as shown in Fig. 5 of the drawings, instead of inserting the stylus aisance clockwise direction, and then shifting the disk I2 until the stylus encounters the right hand end of the slot 30. If the disk I2 is to be shifted in a counterclockwise direction, the stylus is inserted in the aperture 25 opposite the number 31, corresponding to the desired shift, cn the outside of the slot 30, and then shifting the disk I2 until the stylus encounters the left hand end of the slot 30. u

I claim:

1. A cryptographic device comprising a iixed member and a member movable with respect thereto, one of said members having character indicia thereon, the other of said members having an opening with character indicia therealong for alinement with said other character indicia, said last namedmember also having a slot of a length to correspond to a predetermined number of said characters, said ilrst named member also having apertures corresponding to said characters and in alinement with said slot.

2. A cryptographic device comprising a xed member and a member rotatable with respect thereto, one of said members having character indicia thereon circularly disposed, the other of said members having an arcuate space with character indicia therealong for alinement with said other character indicia, said last named member also having an arcuate slot of a length to correspond in angular relationship to a predetermined number of said characters, said rotatable member also having a plurality of apertures corresponding to the characters thereon andin alinement with said slot. i

3. A cryptographic device comprising a fixed cover member and a member therebelow and rotatable with respect thereto, said rotatable member having character indicia thereon circularly disposed, said cover member having a semicircular opening concentric with said character indicia and having character indicia therealong for alinement With said clrcularly disposed indicia, said cover member also having an arcuate slot of a length to correspond in angular relationship to a predetermined number of said characters, said rotatable member also having a plurality of apertures corresponding to said characters thereon and-in alinement with said arcuate slot.l y

, 4. A cryptographic device comprising a xed member and amember rotatable with respect thereto, said rst named member having an arcuate space therein with character indicia therealong, said rotatable member also having character indicia thereon disposed for alinement in said space with said first mentioned character indicia.

5. A cryptographic device comprising a fixed member and a member rotatable with respect l 6. A cryptographic device comprising a coverl member and a member rotatable with respect thereto, said rst named member having an arcuate opening therein with character indicia therealong, said rotatable member also having character indicia thereon clrcularly disposed for alinement in said opening with said iirst mentioned character indicia, said latter character indicia including a repetition of said ilrstmentioned character-indicia. l

7. A cryptographic device comprising a iixed member anda member rotatable with respect thereto, said rotatable member having character indicia thereon, said iixed member having an opening with character indicia, therealong for alinement with said other character indicia, said rst mentioned member also having a slot of a length to correspond in angular relationship to a predeterminednumber of said characters, said rotatable member also having a plurality of aperturescorresponding to' the characters thereon and in alinement with said arcuate slot.

8. A cryptographic device comprising a fixed member and a member rotatable with respect thereto, said rotatable member having character indicia thereon, said fixed member having an opening with character indicia therealong for alinement with said other character indicia, said rst `mentioned member also having a plurality of arcuate slots each of a lengthto correspond in angular relationship to a predetermined numthereto. said rotatable member having charac-' ter indicia thereon. said fixed member having an opening with character (indicia therealong for alinement with said other character indicia, said rst mentioned member also having a plurality of slots each of a length to correspond in angular relationship to a different predetermined number of said characters, said rotatable member also having a plurality of apertures corresponding to the characters thereon and in alinement with said slots.

10. A cryptographic device comprising a fixed member and a member rotatable with respect thereto, said rst named member having character indicia thereon. said character indicia comprising the letters of the alphabet, a space indicator and the unit numbers, said rotatable member having character indicia thereon. the indicia on said rotatable member including the same characters as those on said rst named member and also a repetition thereof.

11. Acryptographic device comprising a xed member anda member rotatable with respect thereto, said first named member having character indicia thereon arcuately disposed, said character indicia comprising the letters of the alphabet, a space indicator and the unit numbers, said rotatable' member having character indicia thereon, the indicia on said rotatable member being circularly arranged and including the same characters as those on said iirst named member and also a repetition thereof.

12. A cryptographic device comprising a xed member and a member rotatable with respect thereto, said rotatable member having character indicia thereon, said xed member having an arcuate opening with character indicia therealong, said.` fixed member also having an arcuate slot of a length to correspond in angular relationship to a predetermined number of said characters, and a set of movement indicating indicia along said arcuate slot.

13. A cryptographic device comprising a fixed member and a member rotatable with respect thereto, said rotatable member` having character indicia thereon, said xed member having an arcuate opening with character indicia therealong, said xed member also having an arcuate slot of a length to correspond in angular relationship to a predetermined number of said characters,and a plurality of sets of movement indicating indicia along said arcuate slot.

14. A cryptographic device comprising a. xed

member and a member rotatable with respect thereto, said rotatable member having characacters, and two sets of number indicia for indicating movement oppositely arranged in increasing order along said slo't.`

15. A cryptographic device comprising a cover member and a member rotatable with respect thereto, said rotatable member having character indicia thereon, said cover member having an arcuate opening with character indicia therealong, said cover member also'having an arcuate slot of a length to correspond in angular vrelationship to a predetermined number of said characters, and movement indicating indicia, said indicia including a set of numbers along said slot with the numbers increasing in one direction and a set of numbers along said slot with the numbers increasing ln another direction.

JAMES C. WOBENSMI'I'H. 

